// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_GESTURE_H_
#define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_GESTURE_H_

#include <memory>

#include "base/macros.h"
#include "base/time/time.h"
#include "content/common/content_export.h"
#include "content/common/input/synthetic_gesture_params.h"

namespace content {

class SyntheticGestureTarget;

// Base class for synthetic gesture implementations. A synthetic gesture class
// is responsible for forwarding InputEvents, simulating the gesture, to a
// SyntheticGestureTarget.
//
// Adding new gesture types involved the following steps:
//   1) Create a sub-type of SyntheticGesture that implements the gesture.
//   2) Extend SyntheticGesture::Create with the new class.
//   3) Add at least one unit test per supported input source type (touch,
//      mouse, etc) to SyntheticGestureController unit tests. The unit tests
//      only checks basic functionality and termination. If the gesture is
//      hooked up to Telemetry its correctness can additionally be tested there.
class CONTENT_EXPORT SyntheticGesture {
public:
    SyntheticGesture();
    virtual ~SyntheticGesture();

    static std::unique_ptr<SyntheticGesture> Create(
        const SyntheticGestureParams& gesture_params);

    enum Result {
        GESTURE_RUNNING,
        GESTURE_FINISHED,
        // Received when the user input parameters for SyntheticPointerAction are
        // invalid.
        POINTER_ACTION_INPUT_INVALID,
        GESTURE_SOURCE_TYPE_NOT_IMPLEMENTED,
        GESTURE_RESULT_MAX = GESTURE_SOURCE_TYPE_NOT_IMPLEMENTED
    };

    // Update the state of the gesture and forward the appropriate events to the
    // platform. This function is called repeatedly by the synthetic gesture
    // controller until it stops returning GESTURE_RUNNING.
    virtual Result ForwardInputEvents(
        const base::TimeTicks& timestamp, SyntheticGestureTarget* target)
        = 0;

protected:
    DISALLOW_COPY_AND_ASSIGN(SyntheticGesture);
};

} // namespace content

#endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_GESTURE_H_
